Arrangement within a yankee cylinder or the like and a roller of a paper machine

ABSTRACT

A Yankee cylinder or the like at the dry end of a paper machine has at least a drying cylinder, a hood covering the drying cylinder, a web guiding means, and a roller. After the drying cylinder at the dry end of the machine, seen in the machine direction, a covered area which above and on the sides is at least mainly covered extends at least to the area of the roller.

CROSS REFERENCES TO RELATED APPLICATIONS

This application is a U.S. national stage application of InternationalApplication No. PCT/FI01/00954, filed Nov. 1, 2001, and claims priorityon Finnish Application No. 20002404 filed Nov. 1, 2000, the disclosuresof both of which applications are incorporated by reference herein.

STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSOREDRESEARCH AND DEVELOPMENT

Not applicable.

BACKGROUND OF THE INVENTION

The invention relates to an arrangement within a Yankee cylinder or thelike and a roller of a paper machine, particularly in order to improvethe runability, to solve linting problems and thus to reduce productiondisturbances, and to improve the fire safety of the paper machine.

In a paper machine a Yankee cylinder dryer and a hood connected to itare generally used to dry a paper web, whereby hot air is blown at ahigh speed from the hood against the paper web on the surface of thecylinder in order to improve the drying effect. The paper web isdetached from the cylinder's surface with the aid of a doctor blade.Already in this phase a substantial amount of lint comes off the paper,particularly from soft tissue. The paper is conveyed with the aid ofmechanical conveying equipment to the roller, and also in this phaselint will come off the paper. At the roller a part of the lint will staywithin the roll being made, but a part of the lint is lost to thesurrounding air, which is hot and flows strongly upwards spreading thelint further into the paper machine room.

As the speed of the paper web is quite high, usually at least 1500m/min, even over 2000 m/min, the created amount of lint is quite high.Due to the high speed, fibres and other particles will quite easily comeoff the paper. Moreover, due to the high speed the lint will get a quitehigh speed in the air flow, and therefore it will be spread effectively.The lint has many harmful effects. It will accumulate as a layer on thesurfaces of structures, particularly on other than vertical surfaces.The lint may come off the surfaces as lumps and fall down on the paperweb so that it causes a production break. The lint may even catch fire,because a part of the equipment is very hot, in spite of theinsulations. Thus a part of the paper machine may even be destroyedwhich causes at least an interruption in the production, but usually italso requires reparations. The lint content in the paper machine roomshould at least not rise above the limits allowed by the healthauthorities. Removal of lint by cleaning the paper machine is a separateoperation, which as such generates costs, and often also lengthens theproduction breaks. If the lint is removed with the aid of a water jet,this can cause additional problems as the equipment and structures getwet.

A number of solutions are known for reducing the linting problems in theregion of a Yankee cylinder dryer and a roller. The publications U.S.Pat. Nos. 5,011,574 and 4,019,953 present equipment to be located closeto the doctor blade, in order to remove the lint created just at thatpoint. The publication WO 97/44525 shows a shaped suction box forsucking away lint from between the Yankee cylinder and the roller. Thepublications thus present some partial solutions, but they do not showan effective total solution for removing the linting problems.

SUMMARY OF THE INVENTION

The object of the invention is to present an arrangement which improvesthe runability of a paper machine, due to the fact that the many harmfuleffects of the lint, which has come off the paper web in the regions ofa Yankee cylinder dryer or the like and a roller, can be obviated or atleast clearly reduced. The object of the invention is more specificallyto improve the efficiency of a paper machine, to increase the productionrate, to improve the quality of the manufactured product, to improve thereliability and the usability of the machine, to improve the fire safetyof the dry end of a paper machine, to reduce the need for cleaning ofthe paper machine and the paper machine room, to improve the air qualityin a paper machine room, and to reduce the noise in the paper machineroom.

At the dry end of the paper machine there is often used a Yankeecylinder dryer or the like containing at least a drying cylinder as wellas a drying cylinder hood with its equipment. For the control of thepaper web there is often used mechanical web guide members, whichthrough contact guide the paper web. After these the paper web is rolledby a roller. If at the dry end of the machine the covered region, whichin the machine direction after the drying cylinder is at least mainlycovered from above and on the sides, continues at least to the region ofthe roller, then the dry end can be quite effectively isolated from therest of the paper machine room, if in this area also the walls arecovered in addition to a cover above. The loose lint can be removed fromthe space formed in this manner with the aid of suction devices.

If the top surface of the covered area is downwards sloping in themachine direction, then the relatively large height required by thedrying cylinder and its hood can be reduced, beginning from a point atthe drying cylinder and continuing in the machine direction in thecovered area, as the equipment typically located in this covered arearequire relatively little space in the height direction. At the dry endof the paper machine the temperature is quite high at some points, andeven if the aim is to isolate the hot parts with the aid of thermalinsulation, the hot air tends to rise upwards and take with it the lint,if there is any in the air.

If at least a portion of the upper part of the covered area is movable,then the covered area can be moved as required, for instance inconnection with the change of rolls or maintenance work. If the topsurface of the covered area is mainly smooth and even at least in themachine direction, then the surface can be kept rather clean, asotherwise lint or other harmful substances may accumulate at thediscontinuing points of the surface.

If the covered area at the drying cylinder is connected to the hoodwithout any substantial step, then it is easy and simple to keep thisarea clean. If the joint between the covered area and the hood is atleast approximately tight, then no lint can pass this way either intothe paper machine room.

If the covered area also covers the roller, so that the lint comingloose at the roller is kept at least mainly under within the coveredarea, then the lint sources of the paper machine's dry end areeffectively covered.

If the lint coming loose from the paper web at the roller area is guidedwith the aid of an air curtain, then the structure does not hardly atall interfere with the operation of the paper machine nor with themaintenance work, but even an air curtain is in some places a sufficientsolution instead of fixed structures in controlling the linting problem.

If an air suspension and/or air redirecting device is used above thepaper web between the drying cylinder and the roller to guide the paperweb and to convey it to the roller, then the paper web is in nomechanical contact with rolls or other web guide members. Such anarrangement creates less lint and only minor amounts of lint come offthe web in this area.

If lint is discharged together with the air from the area of the airsuspension and/or air redirecting device, then also the amount of lintwithin the covered area is even smaller. If a negative pressure isarranged within the space above the air suspension and/or airredirecting device, then this negative pressure prevents the lint comingoff the paper web from spreading into the paper machine room, and therewill be still less problems caused by the lint in this area. However,only a minor negative pressure must be created, so that this negativepressure does not create problems regarding the paper web.

If the negative pressure is arranged with the aid of one or moredischarge channels, then the size, shape, position and the negativepressure of the discharge channel can be chosen so that the dischargechannel creates a desired effect. If there is arranged one or more aircurtains to define said negative pressure space, then there are no wallsnor equipment to hinder operation or maintenance in the same way asthere would be when using fixed structures.

If the outer surfaces of the piping and other equipment are arranged tobe substantially vertical in the negative pressure space above the airsuspension and/or air redirecting devices, whereby the space extends upto the roller, then such surfaces can hardly accumulate any lint. Alsothe top surface of the air suspension and/or air redirecting devicesadvantageously has such a shape that no lint can accumulate there.

If the piping and other equipment are directed through the approximatelyhorizontal wall defining the upper part of the negative pressure space,then neither these structure parts can collect any substantial amountsof lint.

If the covered area between the Yankee cylinder and the roller comprisesa chamber having at its lower part a wall which separates the chamberfrom the space below it, and in which chamber there is arranged apositive pressure with the aid of an air flow, then no dust can passinto this chamber due to the positive pressure. Even a slightoverpressure is sufficient to prevent lint from passing into thechamber. If the supply and discharge piping, lint suction equipment andcontrol and regulation devices are mounted in said chamber, then suchdevices in this space are well protected from lint.

If a blowing equipment is arranged close to the upper surface of thecovered space, which blowing equipment blows pressurised air against thetop surface of the covered area, against the machine direction, then theblowing equipment keeps the air in motion so much that no lint canaccumulate on such a surface. Moreover, such blowing equipment is simpleand inexpensive to manufacture, install and operate.

If air is discharged from the blowing device at a flow rate which is sohigh that no lint is left on the top surface of the covered area, thenthe lint always flowing with the air can not accumulate in these areas.If a plurality of nozzles or nozzle groups and/or directed blowingopenings are arranged to blow against the top surface of the coveredarea, so that due to their combined action the whole covered area or atleast the main part of it is kept free of a lint layer, then the coveredarea can be reliably kept quite clean without any further actions.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is presented in more detail below with reference to theenclosed drawing.

FIG. 1 shows schematically in a side view an arrangement according tothe invention at the dry end of a paper machine.

FIG. 2 shows schematically in a side view an air redirecting and airsuspension conveying arrangement for the paper web according to thearrangement of FIG. 1.

FIG. 3 shows schematically in a three-dimensional view the upperstructure of the covered area of the arrangement according to FIG. 1.

FIG. 4 shows schematically in a side view another arrangement like thatof FIG. 1 at the dry end of a paper machine.

FIG. 5 shows schematically an arrangement like that of FIG. 1, but herea so called through air drying cylinder provided with a wire is used asthe drying cylinder.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The reference numeral 1 in the drawing FIG. 1 represents a Yankeecylinder whose upper parts are completely covered by the halves 2′ and2″ of the hood 2. The arrows a represent basically the blow against thesurface of the paper web. The Yankee cylinder has a doctor blade 3,which detaches the paper web from the surface of the Yankee cylinder.The reference numeral 4 represents web guiding means, with which thetravel of the paper web 5 is guided, and which change the direction ofthe paper web 5 before the roller 6, when required. In order to guidethe paper web before the roller 6 there can be used auxiliary equipment7, for instance the blow box and the support cylinder shown in FIG. 1.In addition it is possible to use different means to process the web,such as a calender (not shown). In the machine direction, represented bythe arrow 8, there is after the hood 2 a covered area 9, which joins thehood section 2″ at 10 so that the top surface of the hood section 2″ atthat point and the top surface of the covered area 9 are at leastapproximately on the same level, and in addition extending at leastapproximately in the same direction. The joint between the hood section2″ and the covered area 9 is at least approximately tight. At that endof the covered area 9 which is towards the roller 6, and where thecovered area 9 with an approximately even top surface ends in themachine direction, there is arranged a blow box 11 being a part of theblowing apparatus, so that this blow box blows air in the direction onthe arrow 12 through a slot at the top surface of the covered area 9,the air having a speed which is so high that no lint or the like is leftin the effective area of the blow.

The reference numeral 13 represents a second blow box which operates inthe same way as the blow box 11. The length of the blow boxes 11, 13 inthe cross direction of the paper machine is approximately the same asthe width of the covered area 9 in the machine cross direction. Ofcourse there can be even more blow boxes, whereby the cleaning effect isin general more reliable, even if the blowing speed would be quite low.Instead of blow boxes it is possible to use nozzle rows which have alarge number of nozzles. In order to have an effective cleaning effectof the blow the covered area 9 is made of a material having a smooth topsurface, such as a coated steel plate. At the end of the covered area 9,close to the roller 6, there is a movable part 14, for instance a damperor the like, which can be moved as a roll is changed. The object of themovable part 14 is to cover the area of the roller 6, so that at leastno substantial amounts of lint can come from this direction either intothe paper machine room. The movable part 14 can be for instance fabricreinforced rubber or plastic mounted in a frame structure which is movedby pneumatic cylinders (not shown). The movable part 14 can even be solarge that it covers, in addition to the end, also a part of the tailend of the top surface of the covered area 9.

The covered area 9 also includes a chamber 15 having at its lower part afloor 16, which forms an approximately tight structure downwards. Thestructure of the chamber 15 is such that during running of the papermachine there may be performed inspection, adjustment and controlactions, even maintenance actions in the chamber 15. Therefore there arearranged passages to the chamber, a door which can be tightly shut, anair lock construction when required, and lighting. A slight overpressurecompared to the air pressure in the paper machine room is maintained inthe chamber 15, so that lint coming from the paper web 5 below thechamber 15 can not travel into the chamber 15. Piping and equipmentrelating to the operation of the paper machine's dry end are located inthe chamber 15.

The input air pipe 17 and the discharge air pipe 18 have been presentedschematically, and they are directed to the side of the paper machine'sdry end, so that they should not present an obstacle for the equipmentabove the covered area 9 or correspondingly for the equipment below thechamber 15. The actual piping within the chamber 15 is not shown. Theinput air pipe 17 is branched into many feed lines, in which thepressure levels and flows are controlled to be suitable for eachapplication. In FIG. 1 the feed line 19 is intended to be used by theweb guiding means 4, and the feed line 20 is intended for the needs ofthe auxiliary equipment 7. Air supplies are provided also for the blowboxes 11 and 13 as well as for providing an overpressure in the chamber15 itself. The discharge air pipe 18 from the chamber 15 also receivesthe discharge air flow from the discharge air pipe 21 of the web guidingmeans 4. The discharge air flow box 22 aids in keeping a slight negativepressure in the space 23 below the chamber 15 by directing the air andwith it the lint into the discharge air pipe 18. An air curtain 24 isused for directing the lint containing air flow, due to the roller 6,into the space 23 and further into the discharge pipe 18. Air curtainscan be used at the hot end of the paper machine also at other locations(not shown), if there is required an even more efficient way to preventharmful spreading of lint into the paper machine room.

In the space 23 the piping and the corresponding devices are at leastapproximately vertical, so that the lint should not accumulate on anysurface and thus cause disturbances in the production. Below the paperweb 5 there are very few devices, so that the paper web 5 at a possibleproduction interruption can without hindrance pass to a conventionalspace (not shown) designed for broke below the paper web 5.

In the arrangement illustrated in FIG. 1 there is a covered area 9 inthe region, which seen in the machine direction is located after theYankee cylinder's 1 hood 2, which hood as such is conventional, wherebythe covered area at the dry end of the paper machine mainly covers thatarea, from which the major part of the lint has been spread into thepaper machine room without an arrangement according to the invention. Amovable part 14 and an air curtain 24 are also used in order to definethe covered area 9. Within the covered area 9 the equipment 4, 7conveying and guiding the paper web 5 are in addition arranged tooperate so that the lint should not be able to accumulate on any areawithin the sphere of influence of the paper web, at least in a harmfulmanner, in order to improve the runability of the paper machine.

FIG. 2 shows in more detail at the reference numeral 25 a web guidingmeans which includes air redirecting devices 26 and 27 fornon-contacting redirecting of the paper web 5, and between these devicesan air suspension conveying device 28 which also in a non-contactingmanner conveys the paper web forward. The arrow 8 shows the machinedirection. The construction of the paper machine's dry end determineswhether both air redirecting devices 26 and 27 are required. Also theangle, at which the paper web 5 must by redirected in the airredirecting devices 26, 27, depends on the construction and dimensioningof the paper machine's dry end. Also the air suspension conveying device28 can have a structure where the paper web slightly changes itsdirection (not shown). It should also be observed that, when required,the air redirecting devices 26, 27 and the air suspension conveyingdevice 28 can also dry the paper web 5. The air supplied by thesedevices to the paper web 5, for the purpose of conveying or redirecting,can even be very hot, which provides an additional drying of the paperweb. The additional drying by air suspension enables the doctoring ofthe web at a higher moisture, whereby less lint is created. According tothe requirements the air supplied by the air redirecting device 26 canbe hotter or colder than the air acting on the paper web 5 in the areaof the air suspension conveying device 28, and the same applies ofcourse also to the air redirecting device 27.

FIG. 3 shows, in the machine direction 8 shown by an arrow, a coveredarea 9 after the halves 2′, 2″ of the hood 2, whereby the upper part ofthe covered area is formed by plates 29 (29′, 29″, 29′″ and so on). Saidplates are joined by seaming, and therefore the seams between the platesform slightly raised ridges in the paper machine's longitudinaldirection. The slot nozzles of the blow boxes 11 and 13 blow air in thedirection of the arrow 12. Said ridges direct the air blows so that theyare kept in the direction of the arrow 12. An additional blow box (notshown) can be mounted, when required, close to the interface between thehood halves 2′, 2″ in order to make the blow even more effective, in thesame way as said blow boxes 11 and 13.

In the arrangement according to FIG. 4 the covered section 9 has aclearly curved upper part, as seen from one side of the paper machine,and also the upper part of the hood 2 is curved. The figure also showsthe rolls 30 of the roller expecting a rolling action. The movable part14 is located at the end of the covered area 9. The air curtains 24 and31 close to the roller direct the flows into the space 23 and furtherout from there into the discharge flow box 22.

The arrangement according to FIG. 5 utilizes a perforated dryingcylinder 32, where the paper web 5 is on a wire 33. Such an arrangementis called through air drying, as there are a plurality of holes in thesurface of the drying cylinder 32, through which air is sucked throughthe wire 33 into the drying cylinder 32, in principle in the directionshown by the arrows b. The use of through air drying generally requiresmore effective additional drying arrangements between the dryingcylinder 32 and the roller 6 than the use of a Yankee cylinder, but inFIG. 5 these devices known as such, for instance drying cylinders, arenot shown. However, it is essential that the lint is removed effectivelyfrom the area between the drying cylinder and the roller, and that thecovered area 9 extends also over these regions.

The arrangement according to the invention can be used not only inconnection with new paper machines, but also in connection with oldmachines when their equipment at the dry end is replaced. A space 23with negative pressure, a chamber 15 and web conveying means 4 accordingto the invention can be arranged below the covered area 9, whereby theobject of the invention is fulfilled. If the hood 2 of the Yankeecylinder 1 is not replaced, then it is possible to arrange blow boxes(not shown) in the upper part of the hood which have the same object andoperating principle as the blow box 11.

The invention is not limited to the enclosed embodiment, but severalmodifications of it are conceivable within the scope of the enclosedclaims.

1. A papermaking machine dry end comprising: a Yankee drying cylinder; ahood covering the Yankee dryer cylinder, the hood connected to a sourceof drying air; a paper web wrapping the Yankee dryer cylinder; a doctorblade engaged with the Yankee drying cylinder, the paper web extendingfrom the doctor blade on the Yankee drying cylinder to a roller whichrolls the paper web, the direction from the doctor blade to the rollerdefining a machine direction; an air suspension device arranged abovethe paper web between the doctor blade and the roller to convey thepaper web in a non-contact manner to the paper roller; and a structurewhich joins the hood, said structure forming a covered area whichextends substantially from the hood covering the Yankee drying cylinderto the roller.
 2. The apparatus of claim 1 wherein the structure forminga covered area is a hood extending to the roller.
 3. The apparatus ofclaim 1 wherein the structure forming a covered area is connected to thehood covering the Yankee dryer cylinder.
 4. The apparatus of claim 1wherein the air suspension device is arranged to redirect the paper webwithin the covered area.
 5. The apparatus of claim 1 wherein the airsuspension device comprises at least one redirecting device and at leastone conveying device.
 6. The apparatus of claim 5 wherein the airsuspension device comprises two redirecting devices and the conveyingdevice is connected between said two redirecting devices.
 7. Theapparatus of claim 1, further comprising a source of heated airconnected to the air suspension device.
 8. A papermaking machine dry endcomprising: a Yankee drying cylinder; a hood covering the Yankee dryercylinder, the hood connected to a source of drying air; a paper webwrapping the Yankee dryer cylinder; a doctor blade engaged with theYankee drying cylinder, the paper web extending from the doctor blade onthe Yankee drying cylinder to a roller which rolls the paper web, thedirection from the doctor blade to the roller defining a machinedirection; an air suspension device arranged above the paper web betweenthe doctor blade and the roller to convey the paper web in a non-contactmanner to the paper roller; a structure forming a covered area whichextends substantially from the hood covering the Yankee drying cylinderand which extends at least to the roller; and wherein the structureforming a covered area comprises a chamber having a lower wall whichseparates the chamber from a space below the chamber and wherein thechamber is connected to a source of positive pressure.
 9. A papermakingmachine dry end comprising: a Yankee drying cylinder; a hood coveringthe Yankee dryer cylinder, the hood connected to a source of drying air;a paper web wrapping the Yankee dryer cylinder; a doctor blade engagedwith the Yankee drying cylinder, the paper web extending from the doctorblade on the Yankee drying cylinder to a roller which rolls the paperweb, the direction from the doctor blade to the roller defining amachine direction; an air suspension device arranged above the paper webbetween the doctor blade and the roller to convey the paper web in anon-contact manner to the paper roller; a structure forming a coveredarea which extends substantially from the hood covering the Yankeedrying cylinder and which extends at least to the roller; and at leastone blowing device positioned to blow air over an upper surface of thestructure forming the covered area.
 10. A papermaking machine dry endcomprising: a Yankee drying cylinder; a hood covering the Yankee dryercylinder, the hood connected to a source of drying air; a paper webwrapping the Yankee dryer cylinder; a doctor blade engaged with theYankee drying cylinder, the paper web extending from the doctor blade onthe Yankee drying cylinder to a roller which rolls the paper web, thedirection from the doctor blade to the roller defining a machinedirection; an air suspension device arranged above the paper web betweenthe doctor blade and the roller to convey the paper web in a non-contactmanner to the paper roller; a structure forming a covered area whichextends substantially from the hood covering the Yankee drying cylinderand which extends at least to the roller; and an air curtain positioneddownstream in the machine direction of the roller, the air curtaindirecting air toward the structure forming the covered area.
 11. Apapermaking machine dry end comprising: a Yankee drying cylinder; a hoodcovering the Yankee dryer cylinder, the hood connected to a source ofdrying air; a paper web wrapping the Yankee dryer cylinder; a doctorblade engaged with the Yankee drying cylinder, the paper web extendingfrom the doctor blade on the Yankee drying cylinder to a roller whichrolls the paper web, the direction from the doctor blade to the rollerdefining a machine direction; an air suspension device arranged abovethe paper web between the doctor blade and the roller to convey thepaper web in a non-contact manner to the paper roller; a structureforming a covered area which extends substantially from the hoodcovering the Yankee drying cylinder and which extends at least to theroller; and a source of negative pressure arranged in communication witha space formed between the air suspension device and the structureforming a covered area.
 12. A papermaking machine dryer sectioncomprising: a drying cylinder having a surface and a plurality of holesin the surface of the drying cylinder, and a source of reduced pressureso that air is sucked into the drying cylinder through the plurality ofholes; a hood covering the drying cylinder, the hood connected to asource of drying air; a wire wrapping the drying cylinder; a paper webon the wire wrapping the dryer cylinder, wherein the paper web extendsfrom the drying cylinder to a roller which rolls the paper web, thedirection from the drying cylinder to the roller defining a machinedirection; an air suspension device arranged above the paper web betweenthe drying cylinder and the roller to convey the paper web in anon-contact manner, at least part of the way to the paper roller; and astructure which joins the hood, said structure forming a covered areawhich extends substantially from the hood covering the drying cylinderto the roller.
 13. A papermaking machine dryer section comprising: adrying cylinder having a surface and a plurality of holes in the surfaceof the drying cylinder, and a source of reduced pressure so that air issucked into the drying cylinder through the plurality of holes; a hoodcovering the drying cylinder, the hood connected to a source of dryingair; a wire wrapping the drying cylinder; a paper web on the wirewrapping the dryer cylinder, wherein the paper web extends from thedrying cylinder to a roller which rolls the paper web, the directionfrom the drying cylinder to the roller defining a machine direction; anair suspension device arranged above the paper web between the dryingcylinder and the roller to convey the paper web in a non-contact manner,at least part of the way to the paper roller; a structure forming acovered area which extends substantially from the hood covering thedrying cylinder to at least the roller; and wherein the structureforming a covered area comprises a chamber having a lower wall whichseparates the chamber from a space below the chamber and wherein thechamber is connected to a source of positive pressure.
 14. A papermakingmachine dryer section comprising: a drying cylinder having a surface anda plurality of holes in the surface of the drying cylinder, and a sourceof reduced pressure so that air is sucked into the drying cylinderthrough the plurality of holes; a hood covering the drying cylinder, thehood connected to a source of drying air; a wire wrapping the dryingcylinder; a paper web on the wire wrapping the dryer cylinder, whereinthe paper web extends from the drying cylinder to a roller which rollsthe paper web, the direction from the drying cylinder to the rollerdefining a machine direction; an air suspension device arranged abovethe paper web between the drying cylinder and the roller to convey thepaper web in a non-contact manner, at least part of the way to the paperroller; a structure forming a covered area which extends substantiallyfrom the hood covering the drying cylinder to at least the roller; andat least one blowing device positioned to blow air over an upper surfaceof the structure forming the covered area.
 15. A papermaking machinedryer section comprising: a drying cylinder having a surface and aplurality of holes in the surface of the drying cylinder, and a sourceof reduced pressure so that air is sucked into the drying cylinderthrough the plurality of holes; a hood covering the drying cylinder, thehood connected to a source of drying air; a wire wrapping the dryingcylinder; a paper web on the wire wrapping the drying cylinder, whereinthe paper web extends from the drying cylinder to a roller which rollsthe paper web, the direction from the drying cylinder to the rollerdefining a machine direction; an air suspension device arranged abovethe paper web between the drying cylinder and the roller to convey thepaper web in a non-contact manner, at least part of the way to the paperroller; a structure forming a covered area which extends substantiallyfrom the hood covering the drying cylinder to at least the roller; andan air curtain positioned downstream in the machine direction of theroller, the air curtain directing air toward the structure forming thecovered area.
 16. A papermaking machine dryer section comprising: adrying cylinder having a surface and a plurality of holes in the surfaceof the drying cylinder, and a source of reduced pressure so that air issucked into the drying cylinder through the plurality of holes; a hoodcovering the drying cylinder, the hood connected to a source of dryingair; a wire wrapping the drying cylinder; a paper web on the wirewrapping the dryer cylinder, wherein the paper web extends from thedrying cylinder to a roller which rolls the paper web, the directionfrom the drying cylinder to the roller defining a machine direction; anair suspension device arranged above the paper web between the dryingcylinder and the roller to convey the paper web in a non-contact manner,at least part of the way to the paper roller; a structure forming acovered area which extends substantially from the hood covering thedrying cylinder to at least the roller; and a source of negativepressure arranged in communication with a space formed between the airsuspension device and the structure forming a covered area.